The primary objective of this study is to provide long-term safety data (up to 12 months) on 1.5mg once daily(QD) SR moxonidine as measured by emerging and worsening adverse events in Stage 1 and Stage 2 hypertensive patients. The secondary objectives are to determine the effect of SR moxonidine on: The change from baseline in sitting diastolic blood pressure measured at trough. Sitting diastolic blood pressure responder rate at trough (reduction of greater than and equal to 10 mm Hg or endpoint of <90 mm Hg). Other blood pressures: Systolic (sitting, supine, standing, and standing 2 minutes) Diastolic (supine, standing, and standing 2 minutes) Heart rate (sitting, supine, standing, and standing 2 minutes).